A dual H-1/F-19 birdcage coil for small animals at 7T MRI

ObjectiveGiven the growing interest in fluorine, it is necessary to develop new multi-tuned RF coils. Therefore, our objective is to design a simple and versatile double-tuned RF coil that can be used as a transmitter and receiver double-tuned coil (H-1 and F-19) or as transmitter-only double-tuned coil. Materials and methodsA high-pass eight-element birdcage coil was built for H-1 and F-19 for a 7T scanner. PIN diodes and cable traps to block unwanted common mode currents in cables were introduced to confer more flexibility to the coil. S-parameters and quality factor were measured in workbench and signal to noise ratio as well as signal intensity profiles in imaging experiments. ResultsBench measurements show S11 values less than -33dB, S21 lower than -13dB and quality factors ratio of the order of 1.8 that are in agreement with good performances of a RF coil, as well as values of -39dB for F-19 and -30dB for H-1 as good detuning values. Signal intensity profiles prove excellent homogeneity at H-1 and F-19. DiscussionWe present a simple structure of a double-tuned high-pass birdcage coil tuned to H-1 and F-19 that shows a great uniformity and sensitivity for F-19.